Curve-drawing instrument



Jan. 20, 1931. I c. F. WEIDMAN 1,789,795

CURVE DRAWING {NSTRUMENT v I Filed Dec. 2a, 1928 INVENTOR WITNESS: ATTORNEY Patented Jan. 20, 1931 mama CHARLES WEIDMAN, OF VICKSBUBG, MISSISSIPPI CURVE-DRAWING INSTRUMENT Application filed December 26, 1928. SeriaINo. 328,377.

This invention relates to measuring instruments of the geometrical type.

An object of the invention comprehends the provision and arrangement of means forming curves of different degrees.

Another object of the invention contemplates a guide for the curve forming means to predetermine the degree thereof.

An additional object of the invention consists in the provision of a support for the guide whereby the curve forming means will not become distorted while in use.

A further object of the invention co1n prises a second guide arm attached to the center of the flexible member having connection With the body of the instrument to revent bulging of the flexible element when the latter is shifted to occupy different positions.

With the above and other objects in View, the invention further consists of the following novel features and details of construction, to be hereinafter more fully described, illustrated in the accompanying drawing and pointed out in the appended claims.

In the drawings Figure 1 isan elevation of my invention shown extended to capacity.

Figure 2 is a view similar to Figure 1 illustrating the retracted position of the flexible element.

Figure 3 isa detail sectional view taken on line 33 of Figurel.

Referring to the drawing in detail, wherein like characters of reference denote corresponding parts, the reference character 10 indicates generally the body portion of the drawing instrument, which can be constructed of wood, metal, Xylonite, or any other suitable material.

A curved arm or flexible element 11, ex-

tended from one end of the body portion of r the instrument, is formed of steel, celluloid, xylonite, etc.

A guide arm 13, formed upon the free end of the flexible element 11, the outermostedge of which 12 forms a tangent tot 118 curved flexible member 11 at the point of curvature X. Said guide arm 13 being adapted to, slide within a groove or raceway 14L in-the body of the instrument having under cut grooves 15 tion in Figure o of the drawing.

The adjacent outer surfaces of the body of the instrument proper and the guide arm 13 are calibrated to indicate the radii of segments of circles or curves capable of being drawn by the present type of instruments.

A slotted arm 17, havingastud 18 horizontally disposed within one end, is adapted to be projected within a slot 19 in the body of the instrument 10. A slot 19 of curved formation is located adjacent the raceway l t. The opposite end of the slotted member or arm 17 is carri'ed'upon the shank 20 of a knurled adjusting screw 21, which alse retains the guide arm 13 in any desired position. A guide arm, such as indicated at 22, is provided with a pin 23, right angularly disposed within the innermost end and projecting through the elongated longitudinally are, posed slot 2 1 in the member 17 and a channel 25 in the body portion of the instrument. I

A head 26, carried upon the outermost end of the guide arm 22, is bifurcated upon the outer end to provide a curved channel 27 to accommodatethe inner sideof the flexible element 11. The guide arm 22 is primarily adapted to prevent irregularities in'the flex-,

ible element 11 when same is shifted to occupy its respective positions.

The slide features for the guide arms 13' and 22 and the slotted member 17 coact in'such manner that the fulcrum point for the guide arm 22 changes as the radius of the circle is increased or diminished commensurate with the regulation ofthe guide arm 13.

' With the present invention, true arcs can I befdrawn without determ ning the center of the circle.

The radius can be quickly adjusted, thus replacing compasses and beam compasses for curves of short radiiand the customarv sets of railroad of longer radii.

curves for curves It is obviously apparent that the flexible element is to be used as a guide for pen or pencil.

, The invention is susceptible of various 5 changes in its form proportions and minor details of construction, and the right is herein reserved to make such changes as properly tall within the scope or" the appended claims. Having described the invention, what is claimed is 1. A drawing instrument comprising a body, a curved flexible element fixed at one end to the body, a guide arm projected from the free end of the element, the body having a raceway in the face thereof within'which the said guide arm is slidably mounted, fins formed upon the side edges of the guide arm adapted for reception within undercut grooves at the sides of the raceway, a slotted member having one end pivoted on the guide arm and the other end slidably mounted within a slot disposed beyond one end of the raceway, and an adjusting element passed through the meeting portions of the guide arm and slotted member to retain the flexible element in adjusted position.

A drawing instrument comprising a body, a flexible element fixed at one end to the body and terminatingat its free end in 3 0, a guide arm, the body being provided with an areuate-shaped raceway having undercut grooves in the walls thereof in which said guide arm is slidably mounted, side fins carried by the guide arm slidably mounted with- 3 5= in the grooves, a slotted member pivotally connected with the guide arm having the opposed end thereof slidably connected with a slot within the body beyond one end of the raceway, a second guide arm slidably mounted upon the slotted member and the body of the instrument, and a head included upon the outermost end of the second guide arm bifurcated to accommodate the adjacent portion of the flexible element. 7

3. A drawing instrument comprising a body, a curved elongated flexible member fixed at one end tothe body and terminating at its free end in a guide arm, the body being provided with an arcuate shaped raceway having undercut grooves in the side walls thereof in which is mounted the said guide arm, side fins carried by the guide arm slidably mounted within the grooves, a slotted member pivotally connected within a slot in the body, a second guide arm slidably mounted upon the slot-ted member and the body of the instrument, a head included upon the outermost end of the second mentioned guide .arm bifurcated to accommodate the so adjacent portion of the flexible element, and a securing elementhaving connection with the meeting portions of the guide arm and the slotted member. V

In testimony whereof I affix my signature.

CHAS. F. WVEIDMAN; 

